JP7160479B2 - electric motor system - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor system, and more particularly to a technique for adjusting current flowing through a stator coil of an electric motor and controlling torque generated in a rotor.

Electric motors that generate torque by electrical energy are used in electric vehicles and the like. 2. Description of the Related Art Some electric motors generate torque in a rotor through electromagnetic interaction between permanent magnets provided in the rotor and stator coils provided in the stator. Generally, the stator coils of an electric motor are connected to an inverter. A polyphase alternating current that generates a rotating magnetic flux around the rotor is supplied to the multiphase windings forming the stator coil by the inverter, and torque is generated in the rotor due to the rotating magnetic flux.

Note that Patent Document 1 below describes an electric motor related to the present invention. This document describes controlling a zero-phase current flowing through a multiphase winding that constitutes a stator coil to generate a radial force on a rotor. A zero-phase current is a current that flows in the same phase through the multiphase windings that constitute the stator coil. Patent Document 2 describes a rotary electric machine control device in which a battery is connected to the neutral point of a multiphase winding that constitutes a stator coil. The zero-phase current flowing through the multiphase windings is switched by the inverter, and the induced electromotive force generated in the multiphase windings boosts the output voltage of the battery. Furthermore, a capacitor as a DC voltage source included in the inverter is charged with the boosted voltage.

2016-42768 publication 2008-306914 publication

In order to increase the torque generated in the rotor of the electric motor, it is conceivable to increase the polyphase AC power input to the electric motor. However, depending on the DC voltage input to the inverter and the DC voltage utilization rate of the inverter, it may be difficult to input sufficient multiphase AC power to the motor, and the required torque may not be obtained. Patent Documents 1 and 2 describe techniques that utilize zero-phase currents in addition to polyphase alternating currents flowing in stator coils. It does not increase torque.

An object of the present invention is to increase the torque produced in the rotor of an electric motor.

The present invention comprises a stator core main body surrounding a rotor, a plurality of teeth arranged in a circular fashion, each protruding from a wall surface of the stator core main body toward the rotor, and a multi-phase winding. a concentrated winding stator coil in which each of the windings is arranged on a tooth determined for each of the windings among the plurality of teeth, and one end of each of the windings of a plurality of phases are connected, An inverter that causes currents to generate rotating magnetic flux around the rotor to flow through the windings of the plurality of phases, and the other ends of the windings of the plurality of phases are connected in common, and a common connection point of the windings of the plurality of phases is connected. a zero-phase switching arm that adjusts the flowing zero-phase current by switching and generates torque in the rotor by the zero-phase current.

Further, the present invention includes a stator core main body portion surrounding a rotor, a plurality of teeth arranged in a circular fashion, each of which protrudes toward the rotor from a wall surface of the stator core main body portion, and a multi-phase rotor. A concentrated winding stator coil having windings, each of which is arranged on one of the plurality of teeth determined for each winding, and one end of each of the plurality of phase windings are connected to the stator coil. , a first inverter for causing a plurality of phase windings to pass a current for generating a rotating magnetic flux around the rotor; and a second inverter that applies a current to the windings of the plurality of phases, adjusts the zero-phase currents flowing through the windings of the plurality of phases by switching, and generates torque in the rotor by the zero-phase currents. characterized by

Preferably, each of the windings has a forward winding and a reverse winding connected in series, and among the plurality of teeth, teeth determined for the forward winding and the reverse winding of each winding are selected. A positive winding and a reverse winding of each of the windings are arranged at , and series connection points of the positive winding and the reverse winding in each of the windings of the plurality of phases are commonly connected.

Preferably, the plurality of phase windings include U-phase, V-phase, and W-phase windings, and the U-phase positive winding, the V-phase reverse winding, and the W-phase positive winding are the first windings. 1 inverter, and a U-phase reverse winding, a V-phase positive winding, and a W-phase reverse winding are connected to the second inverter.

Preferably, the windings of the plurality of phases include U-phase, V-phase and W-phase windings, and the U-phase, V-phase and W-phase windings are positive windings that are not directly connected. and a reverse winding, wherein, among the plurality of teeth, the forward winding and the reverse winding of each phase are arranged on teeth determined for the forward winding and the reverse winding of each phase, and U One end of each of the positive winding of the phase V, the reverse winding of the V phase, and the positive winding of the W phase is connected, and the current that generates the rotating magnetic flux around the rotor is supplied to the positive winding of the U phase, the reverse winding of the V phase, and the positive winding of the W phase. and the W-phase positive winding, and the other ends of the U-phase positive winding, the V-phase reverse winding, and the W-phase positive winding are common. a first said zero-phase switching arm for adjusting a zero-phase current flowing through a common connection point of the U-phase positive winding, the V-phase reverse winding, and the W-phase positive winding, and the U-phase reverse winding; One end of each of the winding, the V-phase positive winding, and the W-phase reverse winding is connected, and the current that generates the rotating magnetic flux around the rotor is supplied to the U-phase reverse winding and the V-phase positive winding. and the second inverter passing through the W-phase reverse winding, and the other ends of the U-phase reverse winding, the V-phase positive winding, and the W-phase reverse winding are connected in common, a second zero-phase switching arm for adjusting a zero-phase current flowing through a common connection point of the U-phase reverse winding, the V-phase positive winding, and the W-phase reverse winding.

Preferably, each of said windings of a plurality of phases comprises a positive winding and a reverse winding that are not directly connected, and one end of each of said positive windings of said plurality of phases is connected to direct rotating magnetic flux around said rotor. The first inverter for causing the generated current to flow through the positive windings of a plurality of phases and the other ends of the positive windings of the plurality of phases are connected in common, and the zero phase flowing to the common connection point of the positive windings of the plurality of phases. The first zero-phase switching arm that adjusts the current is connected to one end of each of the reverse windings of a plurality of phases, and the second current that generates rotating magnetic flux around the rotor flows through the reverse windings of the plurality of phases. and a second zero-phase switching arm, to which the other ends of the reverse windings of a plurality of phases are connected in common, and which adjusts the zero-phase current flowing through a common connection point of the reverse windings of the plurality of phases; Prepare.

According to the present invention, the torque generated in the rotor of the electric motor can be increased.

It is a figure showing the composition of the electric motor system concerning a 1st embodiment. It is a figure which shows the cross section of an electric motor. It is a figure which shows the structure of an inverter control part. It is a figure which shows the structure of a zero phase control part. FIG. 4 is a diagram showing torque when a zero-phase current is constant over time; 6 is a diagram showing torque when the polarity of the zero-phase current is reversed with respect to the conditions of FIG. 5; FIG. FIG. 3 is a diagram showing torque generated in a rotor by zero-phase current and zero-phase magnetic flux; It is a figure which shows the structure of the electric motor system which concerns on 2nd Embodiment. It is a figure which shows the structure of a 2nd inverter control part. It is a figure which shows the structure of the electric motor system which concerns on 3rd Embodiment. It is a figure which shows the structure of the electric motor system which concerns on 4th Embodiment. It is a figure which shows the structure of the electric motor system which concerns on 5th Embodiment.

Each embodiment of the present invention will be described with reference to each drawing. The same components shown in multiple drawings are denoted by the same reference numerals to simplify the description.

FIG. 1 shows the configuration of an electric motor system 1 according to a first embodiment of the invention. The electric motor system 1 includes a battery 10 , an inverter 12 , an electric motor 14 , a zero phase switching arm Z and a control unit 18 . Inverter 12 converts the DC power output from battery 10 into three-phase AC power and outputs the same to electric motor 14 . The rotor of electric motor 14 is rotated by the three-phase AC power output from inverter 12 . A neutral point N of the electric motor 14 is connected to the zero-phase switching arm Z. As will be described later, the switching of the zero-phase switching arm Z adjusts the zero-phase current flowing through each winding of the motor 14, and torque is generated in the rotor not only by the three-phase AC current flowing through each winding but also by the zero-phase current.

A specific configuration and operation of the electric motor system 1 will be described. Electric motor 14 includes a U-phase winding 20U, a V-phase winding 20V, and a W-phase winding 20W that form a concentrated winding stator coil. The electric motor 14 also includes a U-phase terminal 22u, a V-phase terminal 22v, a W-phase terminal 22w, and a rotor (not shown). One end of each of U-phase winding 20U, V-phase winding 20V and W-phase winding 20W is connected at a neutral point N in common. The other end of U-phase winding 20U, the other end of V-phase winding 20V, and the other end of W-phase winding 20W are connected to U-phase terminal 22u, V-phase terminal 22v, and W-phase terminal 22w, respectively. there is A three-phase alternating current flows through the U-phase terminal 22u, the V-phase terminal 22v, and the W-phase terminal 22w. Occur. The rotor rotates in synchronization with the rotating magnetic flux.

The control unit 18 may be configured by an arithmetic processing device, for example, and may operate according to a program stored by itself or a program read from the outside. The control unit 18 performs switching control of the inverter 12 and the zero-phase switching arm Z. FIG.

The inverter 12 comprises switching arms U, V and W; The switching arm U is composed of an upper switching element S1 and a lower switching element S2 connected in series. The switching arm V is composed of an upper switching element S3 and a lower switching element S4 connected in series. The switching arm W is composed of an upper switching element S5 and a lower switching element S6 connected in series.

The switching arms U, V and W are connected in parallel, with their upper ends connected to the positive terminal of the battery 10 and their lower ends connected to the negative terminal of the battery 10 .

A U-phase terminal 22u of the electric motor 14 is connected to a connection point between the upper switching element S1 and the lower switching element S2 in the switching arm U. A V-phase terminal 22v of the electric motor 14 is connected to a connection point between the upper switching element S3 and the lower switching element S4 in the switching arm V. As shown in FIG. A W-phase terminal 22w of the electric motor 14 is connected to a connection point between the upper switching element S5 and the lower switching element S6 in the switching arm W.

The zero-phase switching arm Z includes an upper switching element A1 and a lower switching element A2 connected in series. A neutral point N of the electric motor 14 is connected to a connection point between the upper switching element A1 and the lower switching element A2. The upper end of the upper switching element A1 is connected to the positive terminal of the battery 10 . A lower end of the lower switching element A2 is connected to the negative terminal of the battery 10 .

Semiconductor elements such as IGBTs (Insulated Gate Bipolar Transistors) and MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) may be used for the switching elements of the inverter 12 and the zero-phase switching arm Z. FIG. 1 shows an example in which IGBTs are used as switching elements. A diode D is connected between the collector terminal and the emitter terminal of each IGBT so that the emitter terminal side becomes the anode terminal.

FIG. 2 shows a cross section perpendicular to the axial direction of the electric motor 14 . The electric motor 14 includes a rotor 30 , a stator core 32 and concentrated winding stator coils 36 . The stator core 32 is composed of a stator core body 34 and a plurality of teeth (T1-T12). The stator core body portion 34 has a cylindrical hollow portion. FIG. 2 shows an example in which 12 teeth T1 to T12 are provided. The teeth T1 to T12 are arranged along the circumferential direction on the inner wall surface of the stator core main body portion 34, and protrude inside the stator core 32 (toward the rotor 30). Each of the teeth T1 to T12 has a cross-sectional shape shown in FIG. 2 extending in the axial direction, and a flange protruding in the circumferential direction is formed at the tip of each tooth. Slots 38 are formed between adjacent teeth. That is, 12 slots 38 arranged in the circumferential direction are formed by 12 teeth T1 to T12.

The U-phase winding 20U includes a U-phase positive winding 20U+ and a U-phase reverse winding U-. U-phase positive winding 20U+ is composed of a conductor wire wound around teeth T1 and T7, and U-phase reverse winding 20U- is composed of a conductor wire wound around teeth T4 and T10.

Here, the forward winding and the reverse winding refer to two types of windings in which the direction of winding of the conductive wire with respect to the teeth is opposite. When current flows from the forward winding and the reverse winding to the neutral point, or when current flows from the neutral point to the forward winding and the reverse winding, the tooth with the forward winding and the reverse winding Magnetic fluxes are generated in the teeth on which the lines are provided, in directions opposite to each other.

The V-phase winding 20V has a V-phase positive winding 20V+ and a V-phase reverse winding 20V-. The V-phase positive winding 20V+ is composed of a conductor wire wound around teeth T5 and T11, and the V-phase reverse winding 20V- is composed of a conductor wire wound around teeth T2 and T8.

The W-phase winding 20W includes a W-phase positive winding 20W+ and a W-phase reverse winding 20W-. The W-phase positive winding 20W+ is composed of a conductor wire wound around the teeth T3 and T9, and the W-phase reverse winding 20W- is composed of a conductor wire wound around the teeth T6 and T12.

A three-phase alternating current flows through the U-phase winding 20U (20U+, 20U-), the V-phase winding 20V (20V+, 20V-), and the W-phase winding 20W (20W+, 20W-). generates a rotating magnetic flux Φr. That is, a magnetic flux directed from the outside to the inside and a magnetic flux directed from the inside to the outside appear at intervals of 90° (mechanical angle), and these magnetic fluxes flow through the U-phase winding 20U, the V-phase winding 20V, and the W-phase winding 20W. It rotates in synchronization with the three-phase alternating current.

Thus, electric motor 14 includes rotor 30 , stator core 32 and concentrated winding stator coils 36 . A stator core body 34 surrounds the rotor 30 . Each of the plurality of teeth T1 to T12 protrudes from the wall surface of the stator core main body 34 toward the rotor 30 and is arranged in a circular fashion. The concentrated winding stator coil 36 has U-phase, V-phase and W-phase windings, and is arranged on teeth T1 to T12 that are determined for each winding. Stator core 32, U-phase winding 20U, V-phase winding 20V and W-phase winding 20W form a 2-pole 6-slot concentrated winding stator.

The rotor 30 includes a cylindrical rotor body 40 and four permanent magnets M1 to M4. The rotor body portion 40 is arranged in the hollow portion of the stator core body portion 34 coaxially with the hollow portion. The permanent magnets M1 to M4 extend in the axial direction of the electric motor 14 with the width direction perpendicular to the radial direction. The permanent magnets M1 to M4 are arranged in a circle so that the polarities of adjacent permanent magnets are opposite to each other. Torque is generated in the rotor 30 by the magnetic action between the rotating magnetic flux Φr generated inside the stator core 32 and the permanent magnets M1 to M4 provided in the rotor 30, and the rotor 30 rotates at a rotational speed synchronized with the rotating magnetic flux. to rotate.

In FIG. 2, the direction of the zero-phase current flowing through each winding at a certain time is indicated by black dots and x. A black dot indicates a zero-phase current flowing away from the drawing surface, and an X indicates a zero-phase current flowing toward the drawing surface. When a zero-phase current flows in each winding in the direction shown in FIG. 2, a zero-phase magnetic flux Φ0 is generated in each tooth in the direction indicated by the dashed-dotted arrows in FIG. In the electric motor system 1 according to the embodiment of the present invention, as will be described later, the magnetic action between the zero-phase magnetic flux Φ0 and the rotor 30 adjusts the zero-phase current so that torque is generated in the rotor 30. .

FIG. 3 shows the configuration of the inverter control section 50 included in the control unit 18. As shown in FIG. The inverter control section 50 includes a carrier signal generation section 54, target signal generation sections 52u, 52v and 52w, comparison sections 56u, 56v and 56w, and buffers 58u, 58v and 58w.

The carrier signal generator 54 generates a carrier signal Cr and outputs it to the comparators 56u, 56v and 56w. The carrier signal Cr may be a signal whose temporal waveform is a triangular wave. Target signal generators 52u, 52v, and 52w generate U-phase current flowing through U-phase winding 20U, V-phase current flowing through V-phase winding 20V, and W-phase current flowing through W-phase winding 20W of electric motor 14, respectively. Target signals Su, Sv and Sw indicating target values are generated and output to comparators 56u, 56v and 56w, respectively. The target signals Su, Sv and Sw may be sinusoidal signals with a mutual phase difference of 120°.

The comparator 56u generates a control signal GUu based on the comparison between the target signal Su and the carrier signal Cr, and outputs the control signal GUu to the buffer 58u. That is, the comparison unit 56u generates a control signal GUu that is high while the target signal Su exceeds the carrier signal Cr and low while the target signal Su is equal to or lower than the carrier signal Cr, and outputs the control signal GUu to the buffer 58u. The buffer 58u outputs a control signal GUu and a control signal GLu obtained by inverting the high and low levels of the control signal GUu.

Through similar processing, the comparator 56v generates the control signal GUv based on the comparison between the target signal Sv and the carrier signal Cr, and outputs it to the buffer 58v. The buffer 58v outputs a control signal GUv and a control signal GLv obtained by inverting the high and low levels of the control signal GUv.

Through similar processing, the comparator 56w generates the control signal GUw based on the comparison between the target signal Sw and the carrier signal Cr, and outputs the control signal GUw to the buffer 58w. The buffer 58w outputs a control signal GUw and a control signal GLw obtained by inverting the high and low levels of the control signal GUw.

The upper switching element S1 in the switching arm U in FIG. 1 is turned on when the control signal GUu is high and turned off when the control signal GUu is low. The lower switching element S2 in the switching arm U is turned on when the control signal GLu is high and turned off when the control signal GLu is low.

The upper switching element S3 in the switching arm V in FIG. 1 is turned on when the control signal GUv is high and turned off when the control signal GUv is low. The lower switching element S4 in the switching arm V is turned on when the control signal GLv is high and turned off when the control signal GLv is low.

The upper switching element S5 in the switching arm W in FIG. 1 is turned on when the control signal GUw is high and turned off when the control signal GUw is low. The lower switching element S6 in the switching arm W is turned on when the control signal GLw is high and turned off when the control signal GLw is low.

Inverter control unit 50 controls each switching element included in inverter 12 , so that three-phase alternating current flows through U-phase winding 20U, V-phase winding 20V, and W-phase winding 20W of electric motor 14 , and stator core 32 A rotating magnetic flux is generated in the interior of the rotor 30 , and torque is generated in the rotor 30 by a magnetic action between the rotating magnetic flux and the rotor 30 .

FIG. 4 shows the configuration of the zero phase control section 60 included in the control unit 18. As shown in FIG. The zero phase controller 60 includes a carrier signal generator 54, a zero phase signal generator 52z, a comparator 56z and a buffer 58z.

The carrier signal generator 54 generates a carrier signal Cr and outputs it to the comparator 56z. The zero-phase signal generator 52z generates a zero-phase signal Sz indicating a target value for the zero-phase current, and outputs the zero-phase signal Sz to the comparator 56z. The zero-phase signal Sz may be a sinusoidal signal having a frequency three times that of the target signals Su, Sv and Sw.

The comparator 56z generates a control signal GUz based on the comparison between the zero-phase signal Sz and the carrier signal Cr, and outputs it to the buffer 58z. The buffer 58z outputs a control signal GUz and a control signal GLz obtained by inverting the high and low levels of the control signal GUz.

The upper switching element A1 in the zero-phase switching arm Z in FIG. 1 is turned on when the control signal GUz is high and turned off when the control signal GUz is low. The lower switching element A2 in the zero-phase switching arm Z is turned on when the control signal GLz is high and turned off when the control signal GLz is low.

According to the switching control executed by the zero-phase control unit 60, the zero-phase current such that the zero-phase magnetic flux Φ0 in the stator core 32 generates torque in the rotor 30 is controlled by the U-phase windings 20U, V It flows through the phase winding 20V and the W-phase winding 20W. As a result, not only the three-phase alternating current but also the zero-phase current can contribute to the torque, and the zero-phase current, that is, the zero-phase magnetic flux can increase the torque. In addition, since not only the three-phase AC current but also the zero-phase current contributes to the torque, the efficiency of using the electric power output from the battery 10 is improved. Furthermore, since the zero-phase magnetic flux is distributed over a plurality of teeth and passes through a different magnetic path from that of the rotating magnetic flux, the iron core utilization efficiency of the stator core 32 is improved.

The principle of generating torque in the rotor by the zero-phase magnetic flux will be explained. FIG. 5 shows, as a characteristic for explaining the principle, the torque when the zero-phase current is assumed to be constant over time. The horizontal axis indicates the rotational electrical angle of the rotor, and the vertical axis indicates the torque generated in the rotor. The rotor rotates synchronously with the rotating magnetic flux. The magnitude (absolute value) of the zero-phase current when the torque TQ1 is generated in the rotor is greater than the magnitude (absolute value) of the zero-phase current when the torque TQ2 is generated in the rotor. The magnitude of the zero-phase current when the torque TQ2 is generated in the rotor is greater than the magnitude of the zero-phase current when the torque TQ3 is generated in the rotor.

FIG. 6 shows, as a characteristic for explaining the principle, the torque when the zero-phase current is constant over time and the polarity (flowing direction) of the zero-phase current is reversed with respect to FIG. . The magnitude of the zero-phase current when the torque TQ4 is generated in the rotor is greater than the magnitude of the zero-phase current when the torque TQ5 is generated in the rotor. The magnitude of the zero-phase current when the torque TQ5 is generated in the rotor is greater than the magnitude of the zero-phase current when the torque TQ6 is generated in the rotor.

As shown in FIGS. 5 and 6, the polarity of the torque changes each time the rotational electrical angle increases by 60°. Therefore, with a DC zero-phase current, the direction of the torque generated in the rotor by the zero-phase magnetic flux is not constant, and it is difficult to make the zero-phase magnetic flux contribute to the torque of the rotor.

As is clear from the comparison of FIGS. 5 and 6, when the polarity of the zero-phase current is reversed, the direction of torque generated in the rotor is reversed. Also, the greater the magnitude of the zero-phase current, the greater the magnitude of the torque. Therefore, according to the present embodiment, a sinusoidal zero-phase current, in which the polarity of the zero-phase current is reversed every time the rotational electrical angle increases by 60°, is applied to each winding to keep the direction of the torque constant. It is the electric motor system 1 which concerns. Such a zero-phase current is a zero-phase current with a period of 120° in terms of rotational electrical angle. The frequency of such zero-phase current is three times the frequency of the three-phase AC current flowing through U-phase winding 20U, V-phase winding 20V, and W-phase winding 20W.

This principle of operation will be described with reference to FIG. Adjacent teeth have opposite directions of zero-phase magnetic flux. As shown in FIG. 2, in tooth T1 at a certain time, the zero-phase magnetic flux Φ0 is directed from the inside to the outside. Further, in the tooth T2, the zero-phase magnetic flux Φ0 is directed from the outside to the inside, and in the tooth T3, the zero-phase magnetic flux Φ0 is directed from the inside to the outside. . . , T12, the direction of the zero-phase magnetic flux is alternately reversed. Therefore, by changing the zero-phase current so that the direction of the zero-phase magnetic flux Φ0 is reversed when the rotor 30 rotates from the position of the tooth with the magnetic poles to the position of the adjacent tooth, the magnetic poles of the rotor 30 The directions of the seen zero-phase magnetic fluxes are the same, and torque is generated in a fixed direction. The mechanical angle at which the rotor 30 rotates by the tooth spacing is 30°, and the rotational electrical angle is 60°. That is, the direction of the torque generated in the rotor 30 is made constant by supplying a sinusoidal zero-phase current whose polarity is reversed every time the rotating electrical angle increases by 60°.

FIG. 7 shows the zero-phase current Iz flowing through each winding and the torque Tq generated in the rotor by the zero-phase magnetic flux. The horizontal axis indicates the rotational electrical angle of the rotor, and the vertical axis indicates the zero-phase current Iz and the torque Tq generated in the rotor. The zero-phase current Iz has a period of 120° in terms of rotational electrical angle. The torque Tq repeats a maximum value and a minimum value at intervals of 30 degrees of rotational electrical angle.

FIG. 8 shows the configuration of the electric motor system 2 according to the second embodiment. The electric motor system 2 includes a battery 10 , a first inverter 121 , a second inverter 122 and an electric motor 14 . The first inverter 121 has the same circuit configuration as the inverter 12 shown in FIG. However, to distinguish from inverter 12 shown in FIG. 1, switching arms U, V and W shown in FIG. 1 are shown as switching arms U1, V1 and W1, respectively, in FIG.

The second inverter 122 comprises switching arms U2, V2 and W2. The switching arm U2 is composed of an upper switching element B1 and a lower switching element B2 connected in series. The switching arm V2 is composed of an upper switching element B3 and a lower switching element B4 connected in series. The switching arm W2 is composed of an upper switching element B5 and a lower switching element B6 connected in series.

The switching arms U2, V2 and W2 are connected in parallel, the upper ends of these switching arms being connected to the positive terminal of the battery 10 and the lower ends being connected to the negative terminal of the battery 10. FIG.

FIG. 8 shows a U-phase positive winding 20U+ and a U-phase reverse winding 20U- that constitute the U-phase winding 20U. Similarly, a V-phase positive winding 20V+ and a V-phase reverse winding 20V- that form a V-phase winding 20V are shown, and a W-phase positive winding 20W+ and a W-phase reverse winding that form a W-phase winding 20W. Line 20W- is shown.

In this electric motor system 2, one end of each of U-phase winding 20U, V-phase winding 20V and W-phase winding 20W is connected to first inverter 121, and U-phase winding 20U, V-phase winding 20V and W-phase winding The other end of each winding 20W is connected to the second inverter 122 . That is, in the electric motor system 1 according to the first embodiment, the other end of each of the U-phase winding 20U, the V-phase winding 20V, and the W-phase winding 20W is connected to the neutral point N. In the electric motor system 2 according to the embodiment, the other end of each winding is connected to the second inverter 122 . The other end of U-phase winding 20U is connected to the connection point of switching elements B1 and B2. The other end of V-phase winding 20V is connected to the connection point of switching elements B3 and B4, and the other end of W-phase winding 20W is connected to the connection point of switching elements B5 and B6.

The first inverter 121 is controlled by the inverter control section 50 shown in FIG. 3, like the inverter 12 shown in FIG. FIG. 9 shows the configuration of the second inverter control section 70 included in the control unit 18. As shown in FIG. The second inverter 122 is controlled by the second inverter control section 70 . The second inverter control section 70 includes a carrier signal generation section 54, target signal generation sections 72u, 72v and 72w, a zero phase signal generation section 74, adders 76u, 76v and 76w, comparison sections 56u, 56v and 56w, a buffer 58u, 58v and 58w are provided.

Target signal generators 72u, 72v, and 72w generate U-phase current flowing through U-phase winding 20U, V-phase current flowing through V-phase winding 20V, and W-phase current flowing through W-phase winding 20W of electric motor 14, respectively. Target signals Qu, Qv and Qw indicating target values are generated and output to adders 76u, 76v and 76w, respectively. The target signals Qu, Qv and Qw may be sinusoidal signals with a mutual phase difference of 120°.

Zero-phase signal generation unit 74 generates a zero-phase signal S0 indicating a target value for zero-phase currents flowing through U-phase winding 20U, V-phase winding 20V, and W-phase winding 20W, and adds adders 76u, 76v, and 76w. output to The zero-phase signal S0 may be a sinusoidal signal having a frequency three times that of the target signals Qu, Qv and Qw.

The adder 76u adds the zero-phase signal S0 to the target signal Qu and outputs the resulting U-phase target signal Qu0 to the comparator 56u. The adder 76v adds the zero-phase signal S0 to the target signal Qv, and outputs the resulting V-phase target signal Qv0 to the comparator 56v. The adder 76w adds the zero-phase signal S0 to the target signal Qw, and outputs the resulting W-phase target signal Qw0 to the comparator 56w.

The carrier signal generator 54 generates a carrier signal Cr and outputs it to the comparators 56u, 56v and 56w. The comparator 56u generates a control signal FUu based on the comparison between the target signal Qu0 and the carrier signal Cr, and outputs it to the buffer 58u. The buffer 58u outputs a control signal FUu and a control signal FLu obtained by inverting the high and low levels of the control signal FUu.

The comparator 56v generates a control signal FUv based on the comparison between the target signal Qv0 and the carrier signal Cr, and outputs it to the buffer 58v. The buffer 58v outputs a control signal FUv and a control signal FLv obtained by inverting the high and low levels of the control signal FUv. The comparator 56w generates a control signal FUw based on the comparison between the target signal Qw0 and the carrier signal Cr, and outputs it to the buffer 58w. The buffer 58w outputs a control signal FUw and a control signal FLw obtained by inverting the high and low levels of the control signal FUw.

The upper switching element B1 of the switching arm U2 in FIG. 8 is turned on when the control signal FUu is high and turned off when the control signal FUu is low. The lower switching element B2 of the switching arm U2 is turned on when the control signal FLu is high and turned off when the control signal FLu is low.

The upper switching element B3 of the switching arm V2 is turned on when the control signal FUv is high and turned off when the control signal FUv is low. The lower switching element B4 of the switching arm V2 is turned on when the control signal FLv is high and turned off when the control signal FLv is low.

The upper switching element B5 of the switching arm W2 is turned on when the control signal FUw is high and turned off when the control signal FUw is low. The lower switching element B6 of the switching arm W2 is turned on when the control signal FLw is high and turned off when the control signal FLw is low.

First inverter 121 and second inverter 122 are controlled by inverter control unit 50 and second inverter control unit 70, and three-phase alternating current is applied to U-phase winding 20U, V-phase winding 20V and W-phase winding 20W of electric motor 14. A current flows and a rotating magnetic flux is generated inside the stator core 32 . Second inverter 122 is controlled by second inverter control unit 70, so that U-phase winding 20U, V-phase winding 20V, and W-phase winding 20W of electric motor 14 have zero-phase voltages as shown in FIG. A current flows, and torque is generated in the rotor 30 due to the magnetic action between the zero-phase magnetic flux Φ0 based on this zero-phase current and the rotor 30 .

FIG. 10 shows the configuration of the electric motor system 3 according to the third embodiment. This electric motor system 3 includes a series connection point of the U-phase positive winding 20U+ and the U-phase reverse winding 20U- in the electric motor system 2 according to the second embodiment, the V-phase positive winding 20V+ and the V-phase reverse winding 20V-. and the series connection points of the W-phase positive winding 20W+ and the W-phase reverse winding 20W− are commonly connected at the neutral point N, and furthermore, the V-phase positive winding 20V+ and the V-phase reverse winding It replaces the winding 20V-. Operations of the first inverter 121 and the second inverter 122 are the same as those in the second embodiment.

The technical significance of exchanging the V-phase positive winding 20V+ and the V-phase reverse winding 20V- will be described. In the electric motor 14 of the first embodiment, as shown in FIG. 2, currents flow in the same direction through a plurality of conductors in one slot. If the V-phase positive winding 20V+ and the V-phase reverse winding 20V− are interchanged with respect to FIG. In slots other than the slots where the U-phase reverse winding 20U- and the W-phase positive winding 20W+ are present, the currents flowing in the adjacent windings are in opposite directions, and the magnetic fluxes weaken each other. As a result, the spatial period of the torque due to the zero-phase magnetic flux is 180 degrees in rotational electrical angle and 90 degrees in mechanical angle. Therefore, when the rotor 30 rotates at the same speed, the pulsation frequency of the torque due to the zero-phase magnetic flux Φ0 becomes smaller than in the electric motor system 1 according to the first embodiment.

In the above description, an embodiment has been described in which the first inverter 121 is controlled by the inverter control section 50 and the second inverter 122 is controlled by the second inverter control section 70 . In addition to such a configuration, the first inverter 121 and the second inverter 122 may be configured to be controlled by the second inverter control section 70 provided individually for each.

FIG. 11 shows the configuration of the electric motor system 4 according to the fourth embodiment. In this electric motor system 4, the common connection point of the U-phase positive winding 20U+, the V-phase reverse winding 20V-, and the W-phase positive winding 20W+ in the electric motor system 3 according to the third embodiment is connected to the first zero-phase switching arm Z1. A common connection point of the U-phase reverse winding 20U-, the V-phase positive winding 20V+ and the W-phase reverse winding 20W- is connected to the second zero-phase switching arm Z2. The forward and reverse windings are provided separately for each phase and are not directly connected.

The first zero-phase switching arm Z1 includes series-connected switching elements A11 and A21. A common connection point of the U-phase positive winding 20U+, the V-phase reverse winding 20V-, and the W-phase positive winding 20W+ is connected to the connection point of the switching elements A11 and A21. The upper end of the switching element A11 is connected to the positive terminal of the battery 10, and the lower end of the switching element A21 is connected to the negative terminal of the battery 10. FIG.

The second zero-phase switching arm Z2 includes series-connected switching elements A12 and A22. A common connection point of the U-phase reverse winding 20U-, the V-phase positive winding 20V+ and the W-phase reverse winding 20W- is connected to the connection point of the switching elements A12 and A22. The upper end of the switching element A12 is connected to the positive terminal of the battery 10, and the lower end of the switching element A22 is connected to the negative terminal of the battery 10.

Switching elements A11 and A12 forming switching arm Z1 adjust the zero-phase current flowing through U-phase positive winding 20U+, V-phase reverse winding 20V-, and W-phase positive winding 20W+. Switching elements A21 and A22 forming switching arm Z2 adjust the zero-phase current flowing through U-phase reverse winding 20U-, V-phase positive winding 20V+ and W-phase reverse winding 20W-.

As a result, U-phase positive winding 20U+, V-phase reverse winding 20V-, W-phase positive winding 20W+, U-phase reverse winding 20U-, V-phase positive winding 20V+, and W-phase reverse winding 20W- , a zero-phase magnetic flux is generated that causes the rotor 30 to generate torque.

FIG. 12 shows the configuration of the electric motor system 5 according to the fifth embodiment. This electric motor system 5 is obtained by replacing the V-phase positive winding 20V+ and the V-phase reverse winding 20V- in the electric motor system 4 according to the fourth embodiment. In the electric motor system 4 according to the fourth embodiment, the spatial period of the torque due to the zero-phase magnetic flux is 180 degrees in rotational electrical angle and 90 degrees in mechanical angle. The spatial period of the torque due to the phase magnetic flux is 60 degrees in rotational electrical angle and 30 degrees in mechanical angle.

1 to 5 electric motor system, 10 battery, 12 inverter, 121 first inverter, 122 second inverter, 14 electric motor, 18 control unit, 20U U-phase winding, 20V V-phase winding, 20W W-phase winding, 20U+U Phase positive winding, 20U- U phase reverse winding, 20V+ V phase positive winding, 20V- V phase reverse winding, 20W+ W phase positive winding, 20W- W phase reverse winding, 22u U phase terminal, 22v V-phase terminal, 22w W-phase terminal, 30 rotor, 32 stator core, 34 stator core main body, 36 concentrated winding stator coil, 38 slot, 40 rotor main body, 50 inverter control section, 52u, 52v, 52w, 72u, 72v, 72w target signal generator 52z, 74 zero phase signal generator 54 carrier signal generator 56u, 56v, 56w, 56z comparator 58u, 58v, 58w, 58z buffer 60 zero phase controller 70 second inverter Controller, 76u, 76v, 76w Adder, U, V, W, U1, V1, W1, U2, V2, W2 Switching arm, Z, Z1, Z2 Zero-phase switching arm, S1 to S6, B1 to B6, A1 , A2, A11, A12, A21, A22 switching elements, T1 to T12 teeth, M1 to M4 permanent magnets, Φr rotating magnetic flux, and Φ0 zero-phase magnetic flux.

Claims (6)

a stator core main body surrounding the rotor;
a plurality of teeth arranged in a circular fashion, each of which protrudes from a wall surface of the stator core main body toward the rotor;
a concentrated winding stator coil comprising windings of a plurality of phases, wherein each of the windings is arranged on one of the plurality of teeth that is determined for each of the windings;
an inverter connected to one end of each of the windings of a plurality of phases, and causing a current to generate a rotating magnetic flux around the rotor to flow through the windings of the plurality of phases;
The other ends of the windings of the plurality of phases are connected in common, the zero-phase current flowing through the common connection point of the windings of the plurality of phases is adjusted by switching, and the zero-phase current generates torque in the rotor. A motor system comprising: a zero-phase switching arm; a stator core main body surrounding the rotor;
a plurality of teeth arranged in a circular fashion, each of which protrudes from a wall surface of the stator core main body toward the rotor;
a concentrated winding stator coil comprising windings of a plurality of phases, wherein each of the windings is arranged on one of the plurality of teeth that is determined for each of the windings;
a first inverter connected to one end of each of the windings of a plurality of phases and supplying a current to the windings of the plurality of phases to generate a rotating magnetic flux around the rotor;
The other ends of the windings of the plurality of phases are connected to each other, and a current that generates rotating magnetic flux around the rotor flows through the windings of the plurality of phases, and the zero-phase current flowing through the windings of the plurality of phases is switched . and a second inverter for generating torque in the rotor by the zero-phase current. In the electric motor system according to claim 2,
Each of the windings has a forward winding and a reverse winding connected in series, and among the plurality of teeth, the tooth determined for the forward winding and the reverse winding of each winding is connected to each A forward winding and a reverse winding of said winding are arranged,
An electric motor system, wherein series connection points of forward windings and reverse windings in each of said windings of a plurality of phases are commonly connected. In the electric motor system according to claim 3,
U-phase, V-phase and W-phase windings are provided as the multi-phase windings,
A U-phase positive winding, a V-phase reverse winding, and a W-phase positive winding are connected to the first inverter,
A motor system, wherein a U-phase reverse winding, a V-phase positive winding, and a W-phase reverse winding are connected to the second inverter. In the electric motor system according to claim 1,
U-phase, V-phase and W-phase windings are provided as the plurality of phase windings,
each of said windings of phases U, V and W comprises a forward winding and a reverse winding that are not directly connected;
The positive winding and the reverse winding of each phase are arranged on teeth determined for the positive winding and the reverse winding of each phase among the plurality of teeth,
One end of each of the U-phase positive winding, the V-phase reverse winding, and the W-phase positive winding is connected, and the current that generates the rotating magnetic flux around the rotor is supplied to the U-phase positive winding, the V-phase positive winding, and the V-phase positive winding. the first inverter that flows through the reverse winding of the phase and the positive winding of the W phase;
The other ends of the U-phase positive winding, the V-phase reverse winding, and the W-phase positive winding are connected in common to connect the U-phase positive winding, the V-phase reverse winding, and the W-phase positive winding. a first said zero-phase switching arm for regulating the zero-phase current flowing through the common junction of the positive windings;
One end of each of the U-phase reverse winding, the V-phase positive winding, and the W-phase reverse winding is connected to generate a rotating magnetic flux around the rotor. a second inverter that flows through the positive winding of the phase and the reverse winding of the W phase;
The other ends of the U-phase reverse winding, the V-phase positive winding, and the W-phase reverse winding are connected in common to form the U-phase reverse winding, the V-phase positive winding, and the W-phase reverse winding. and a second said zero-phase switching arm for adjusting the zero-phase current flowing through the common connection point of the reverse windings. In the electric motor system according to claim 1,
each of said windings of a plurality of phases comprising a forward winding and a reverse winding that are not directly connected;
a first inverter to which one end of each of the positive windings of a plurality of phases is connected so that a current for generating a rotating magnetic flux around the rotor flows through the positive windings of the plurality of phases;
a first zero-phase switching arm, to which the other ends of the positive windings of a plurality of phases are connected in common, and which adjusts a zero-phase current flowing through a common connection point of the positive windings of the plurality of phases;
a second inverter connected to one end of each of the reverse windings of a plurality of phases, and supplying a current to the reverse windings of the plurality of phases to generate a rotating magnetic flux around the rotor;
and a second zero-phase switching arm, to which the other ends of the reverse windings of the plurality of phases are commonly connected, and which adjusts the zero-phase current flowing through the common connection point of the reverse windings of the plurality of phases. and motor system.

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